Cng/Lpg Gaseous Engine Prep Pkg-inc: hardened intake valves, exhaust valves & valve seats(REQ: 99L Engine)This package does not include CNG/LPG fuel tanks, lines, etc. Vehicle will be equipped with the standard factory gasoline fuel system. Additional equipment combined with a Certified calibration reflash is required, from an external upfitter, to convert the vehicle to a CNG/LPG-fueled vehicle. Ford Motor Company does not provide an exhaust or evaporative emissions certificate with this option when converted to use CNG or LPG fuel. Ford does not represent that a vehicle converted to use CNG or LPG will comply with all applicable U.S. or Canadian safety standards. It is the responsibility of the final stage manufacturer (body builder, installer, alterer or subsequent stage manufacturer) to determine that any vehicle converted to use CNG or LPG complies with U.S. Federal, California, or Canadian exhaust and evaporative emission requirements, Federal fuel economy standards, U.S. and Canadian safety standards, labeling, and any other requirements